%I #16 May 17 2016 11:57:30
%S 1,5,9,10,15,16,20,21,23,25,29,30,32,35,37,40,42,43,44,45,49,50,51,54,
%T 55,58,60,61,65,66,68,70,72,75,76,79,80,81,83,85,86,87,89,90,93,94,95,
%U 98,99
%N Numbers n such that 6n - 5 is not prime.
%F a(n) ~ n. - _Charles R Greathouse IV_, May 09 2016
%e a(2) = 5 because 6 * 5 - 5 = 25 that is composite.
%t Select[Range[100], Not[PrimeQ[6# - 5]] &] (* _Alonso del Arte_, May 09 2016 *)
%o (PARI) is(n)=!isprime(6*n-5) \\ _Charles R Greathouse IV_, May 09 2016
%K nonn,easy
%O 1,2
%A _Carlos Valencia Alonso_, May 09 2016